Samsung 16mm f/2.4 i-Function NX20

Samsung 16mm f/2.4 i-Function NX20

How does this bargain large aperture wide angle lens perform on the NX20?

I am updating resolution numbers from my review of the lens on NX11. Picture from NX11 review.

Corrected Optical Performance

Please click on the tab you want to view. Only 1 tab may be active at a time. MTF, Distortion, and Lat CA data acquired using Imatest

Comments on the Results

These are corrected results from LR4.1 (no option to leave uncorrected with this lens and LR4.1). The lens is extremely sharp in the center stopped down 1 stop, but the corners are lag a little behind only just reaching very good levels. Across the frame the lens is weak at f/2.4.

Distortion is well corrected and virtually negligible.

Lateral CA is visible, but not terrible. It isn’t well corrected by default in LR4.1, the profile they use to correct distortion for this lens must not remove Lateral CA.

Purple fringing is visible. It is mostly in the corners on the uncorrected images. It improves on stepping down, but is still visible.

Coma is very noticeable wide open, but disappears when stepping down the lens.

The lens is extremely resistant to flare. I found it difficult to get any sort of flare spots to appear.

I measured the focal length again, and got within 0.5 mm of my previous result with 17.2mm at 1:53 magnification. Uncorrected it is wider than 16mm field of view.

Pros and Cons

Bottom Line

Not a lot has changed since the NX11 review, since this has been corrected by Lightroom, the corner performance suffers some. Even though performance looks bad at f/2.4, Imatest is reporting that the image is under-sharpened significantly compared to f/5.6. This means that with processing you will make it perform better, and I notice that the default RAW looked less sharp than the JPEG preview image. It would be worth using a different sharpening preset for f/2.4 vs f/5.6.

Secondly, there are rumors that the corners are worse on the 20 MP sensor than they are on the NX11. If they are, this is only true at infinity focus. I think the corners on my NX200 looked slightly worse than they did on the NX11, but the center is also noticeably sharper, so this makes the corners look worse than they are.

I think at infinity focus you will take a bit of a hit vs the NX11 with this lens, but resizing both images to 10 MP or so and they shouldn’t be that different. I believe any difference here is when the lens is focused at infinity the elements are closest to the sensor, which means the light will be hitting the sensor at a steeper angle, and my thought is the 20 MP sensor with smaller pixels doesn’t do quite as well in this regard (similar to issues with NEX 7 corner performance).

This is subjective since the lens does well on test charts, which at 1:53 magnification are decently close to infinity focus, but looking at actual images I feel I should bring it up. I will try a more specific test later.

Finally, the lens has a small amount of field curvature (I think unrelated to the second point), where if you want sharp across the frame image, focus closer to the outer points. Don’t try to focus at the center for best corner performance.

Overall this lens is a great lens, compact and good performing. If you want to cover this range and don’t care about size or giving up about 2 f/stops the upcoming 12-24 mm f/4-5.6 might be worth the wait. I like this lens though as it is great size for the aperture and field of view.

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Gallery

The gallery images are © 2012 Eric Tastad, and may only be used for personal evaluation of the lenses. Click the play button and click “visit gallery” in the upper right to download full size images.

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